Currently various imaging means or methods are used to assess functional disturbances, which allow the acquisition of dynamic three-dimensional images, e.g. ultrasound, magnetic resonance tomography (MRT), Positron Emission Tomography (PET) or Single Proton Emission Computed Tomography (SPECT). “Dynamic” is intended to mean that a time sequence of images is acquired, which, for example, allows visualisation of the movement of the heart. Particularly suitable for this are real-time 3D ultrasound systems with which real-time images can be acquired in 3D.
During one exemplary functional evaluation, the wall of a cavity, such as the heart chamber, is observed and its movement is followed. A disturbance e.g. of the heart muscle activity can be detected, for example, in that the heart chamber wall is not contracting simultaneously everywhere and not everywhere with the same strength. This can be determined by automatically detecting and observing the contours of the chamber (e.g. the left or right ventricle or an atrium). The inner wall of the cavity can then be represented as a type of grid network structure (as was described for example in EP 0 961 135 by the Applicant) whose surface is approximated, for example, by triangles (such grid network structure is referred to below as “pouch”). The pouch is then divided into sections, and the movement of the individual sections is followed in order to determine, for example, the contraction time and respective delay times compared to the section with the earliest contraction. The cavity (e.g. of the heart) can also be divided into volume sections, whose change in volume e.g. over a heartbeat is observed. The results of such evaluations are often represented in the form of what is known as a “polar plot”, which e.g. shows the heart spread out as on a flat land map, in which a sector in the polar plot is allocated to each section of the heart chamber wall. A polar plot therefore represents virtually a flat map e.g. of a heart chamber, on which certain functional values such as contraction time or maximum volume change are applied in a color-coded manner.
Such evaluations are carried out, for example, with the software programs TomTec Left Ventricular Analysis, TomTec Right Ventricular Analysis and 4D Left Ventricular Analysis Cardiac Resynchronization Therapy and e.g. with PET/SPECT softwares. The evaluation methods used in these programs for obtaining data sets with functional values are described for example in the following articles:    Kapetanakis, Monaghan L: “Real-Time Three-Dimensional Echocardiography—A Novel Technique to Quantify Global Left Ventricular Mechanical Dyssynchrony”, Circulation. 2005; 112:992-1000.    Bax J J, Abraham T, Barold S S, Breithardt O A, Mark D B, Monaghan M G, Nihoyannopoulo: “Cardiac resynchronization therapy: Part 1—issues before device implantation”, J Am Coll Cardiol. 2005 Dec. 20; 46 (12):2168-82.    Monaghan M J: “Role of real time 3D echocardiography in evaluating the left ventricle”, Heart. 2006 January; 92(1):131-6.    Lipiec P, Piewka M, Kasprzak J D: “Automated quantification of left-ventricular volumes and function: a novel clinical tool?” Congress of the European Society of Cardiology 2003.
The results of such evaluations are then transmitted as a multidimensional data set with functional values, e.g. in the form of a pouch which can be built up from points, triangles, or the like and may additionally contain functional values, as a polar plot or as a data table.
A cardiologist is often faced with having to compare different functional evaluations of the heart chambers with one another, e.g. in a stress echo test, in which functionally disturbed areas in the myocardium of the left ventricle are evaluated at rest and during stress of the patient. In clinical routine a comparison between the resting and the stressed state has hitherto been always carried out by subjective assessment by the doctor. Occasionally, data obtained by different imaging means must be compared with one another, e.g. a perfusion image of the heart obtained by PET or SPECT with a dynamic data set showing the activity of the heart chamber wall.
A standardised, qualitative comparison is only available on the basis of 2D sections of the heart. This standard was developed by the American Congress of Cardiology (ACC) and by the American Heart Association (AHA). However, this method only offers very limited spatial scanning of the left ventricle, since only a few specified 2D sections (three long axis sections and one short axis section) are assessed by the observer and not the whole ventricle. The findings are therefore not easily comparable because of their intra- and inter-observer-variability.
In the prior art, therefore, no methods for evaluating dynamic images, e.g. of the heart, are available which permit complete spatial comparative evaluation and hence provide an objective medical finding. With the different formats in which the functional evaluations of the heart chambers are made available, there is no possibility for considering different examination results at a glance.